Gas-engine.



' R. MILLER.

GAS ENGINE.

APPLICATION FILED JAN.19, 1909.

1,1 30,419. Patented Mar. 2, 1915.

lslslll);

mmmnf sus ra ROBERT MILLER, 0F NEW YORK, N. Y., AS-SIGNOR TO R. M. OWENAND COMPANY, OE

NEW YORK, N. Y., A CORPORATION OF NEW YORK.

GAS-ENGINE.

Specication of Letters Patent.

Application led January 19, 1909. Serial No. 473,(546.

T0 all 'whom t may concern.'

Be it known that I, ROBERT MILLER, a citi- Zen of ,the United States ofAmerica, residing at New York city, in the county of New York and Stateof New York, have invented certain new and .useful Improvements inGas-Engines, of which the following is a specification, reference beinghad therein to the accompanying drawing.

This invention relates to vacuum exhaust gas engines wherein a piston isused for the double purpose of imparting the result of the explosion tothe crank-shaft, and of creating a vacuum in a separate chamber to drawout the products of combustion which linger after the force'of theexhaust becomes spent.

My object is to provide an engine of the above type in which theexplosion chamber will during all loads be much more equally scavenged,kept cooler, and receive a more constant mixture, thereby obtaininggreater flexibility of action, power, durability and efficiency, andalso effecting a greater'saving in fuel and lubricants. n

It shouldbe explaimed beforehand that the work of scavenging thecylinder is pro- A portionate to the strength and volume of the vacuum.Therefore it is apparent that a vacuum created in the crank-case by thereturn stroke ofthe power piston, as in ,an ordinary two-cycle engine,is necessarily weak owing to leakage around the crank bearings. In mydevice the vacuum is formed in a separate tight vacuum chamber whollydisconnected from and independent of the crank-case, whereby leakage isreduced to a minimum, and a high, strong and efiicient vacuum can becreated of sufficient volume. Furthermore, I provide a method of andapparatus for shutting off the vacuum chamber from the explosion chamberbefore opening the fuel inlet, thereby not depending on displacement ofold charge by the new charge, and preventing the fuel from following theresidual spent gases out of the explosion chamber and becoming wasted.Hence my invention comprises virtually the same method of expulsion asthe four cycle engine in that it first permits the engine to exhaust byrelease of the red gases which pass out under their -own pressure, andsecondly by removing a fixed quantity of the residual products ofcombustion. An additional source of cooling consists in the reflexshrinkage of the burned gases as they pass from the power cylinder tothe vacuum cylinder due to the drop in temperature owing to the previousexpansion caused by differences in pressure. Therefore the vacuumchamber should be as large as possible in proportion to the size of thepower cylinder.

It is also a great advantage and is my object to remove as much burnedgas from the power cylinder on light loads as on full loads. If lessburned gas be removed on light loads than on heavy loads, then the freshcharge will be fouled with too great a proportion of burned gas, wherebyignition is rendered uncertain and the flexibility Patented Mar. a,i915.,

of the engine unreliable, In this respect my object is to duplicate asnear as practicable, the positive equal displacement of the burned gaswhich takes place in the four cycle engine at all loa-ds.

To these ends my invention consists in the peculiar features andcombinations of parts more fully described hereinafter and pointed outin the claims.

In the accompanying drawings, Figure l represents a sectional elevationof my invention, and Figs. 2 and 3 are modifications.

A For purposes of illustration, the power cylinder l, vacuum cylinder 2,and crank case 3 are shown cast in two pieces bolted together, no watervjacket or cooling fianges being shown, although in practice one or theother will probably be desirable. The differential piston comprises twoprincipal elements, the power piston 4 and vacuum piston 5. This vacuumpiston and cylinder are much larger in diameter than the power cylinderand its piston, whereby ample room is allowed in the vacuum cylinder forthe reception of the burned residual gases which are drawn out of thepower cylinder' on the down-stroke of the two pistons. Both pistons arepreferably cast in one piece and are provided with the usual packingrings 6 and are connected to a pitman 7 which is attached to a crank 8on crank shaft 18. The valve connections consist of a pneumaticallyactuated inlet valve 9 controlling the tween the two cylinders and iscommanded by a rotary valve 16 having an arm 19 which it; may beconnected with any moving parts of the engine and timed'to operate aspresently described. The spark plug 21 in the head of the cylinder 1lires the gas at the proper moment as will now be described.

Assuming that a'proper charge of gas has just been admitted to the powercylinder and is under compression, the .explosion will drive the pistondownward until the exhaust port 10 is uncovered, whereupon the resaleased products of combustion pass out through the. exhaust pipe 11lifting the check valve 12 against the spring 13 in doing so. 'llhecontinued downward movement of the two pistons will create a strongvacuum S@ in the vacuum cylinder 2, whereupon the by l pass valve 16will be thrown open after the close of the exhaust and the residual gasdrawn into the vacuum cylinder. An equilibrium will then be establishedbetween the @t two cylinders. 'llhis leaves a vacuum inthe powercylinder practically free from burnt gases and in good condition to drawin a fresh explosive charge. The further rotation of the crank shaftcloses the by-pass c@ valve and seals the explosion chamber and theinlet valve having been given the proper lead is then uncovered andopened by the vacuum left in the explosion chamber and draws in a freshcharge of explosive gases.

35 `When the power piston moves upward toward compression the vacuumpiston follows, expelling the dead gases from the vacuum chamber throughthe by-pass 15 and exhaust 12. The continued upward move- 5@ ment of thepower piston compresses the combustible gases, and when they are ignitedthe cycle of operations 'just described is repeated.

ln clearing the cylinder of the yspent gases,

et they rst pass out of theexhaust through the power of their ownpressure, but a certain portion always lingers in the power cylinder,and it is this portion which is removed through the medium of the vacuumthat fol- 60 lows. The exhaust port is timed to close in advance of theopening of the inlet *port so that it is impossible for any ofthe freshcharge of gas to be drawn out through the exhaust port with the spentgases and es wasted. ln this respect my invention ehfects amonio greateconomy in the consumption of fuel the double exhaust construction whichremoves the residue of burned gases, prevents the fouling of the freshcharge and produces a much more uniform explosion and exible andreliable operation under both light and heavy loads.

llt is apparent that theparticular mechanism whereby l accomplish theseadvantages might be varied in numerous ways such, for instance, as shownin Fig. 2 wherein a vacuum chamber 22 is separated farther from thepower cylinder 29 through the medium of a pipe 23 having a valve 28which is adapted to cop'erate with an exhaust pipe Iton. Between the twois located a chamber 31 formed by disks 32.. The power cylinder isconnected with the vacuum cylinder and the piping and valves are allarranged and adapted to operate in substantially the same manner asthose shown in Fig.. 1.,

Having thus described my invention, what l claim as new and desire tosecure by Letters Patent, is:

1. ln a gas engine of the two-cycle type, an explosion cylinder and apiston working therein, a vacuum chamber, a valved by-pass between theexplosion chamber and the vacuum chamber, a valved exhaust port for theexplosion chamber, a fuel inlet port therefor, and means for opening thesaid by-pass and establishing communication between the inl terior ofthe explosion cylinder and the vacuum chamber after the force of theexhaust blast has practically spent itself.

2. ln a gas engine, a pair of cylinders of diderent size formingrespectively explosion and vacuum chambers, a diderential piston in saidcylinders, in combination with means consisting of a valved by-passleading from the explosion chamber to the vacuum chamber, a valvedexhaust port, a fuel inlet port, means for opening the lay-pass andclosing the exhaust port and establishing communication between the twocylinder chambers after the force of the exhaust blast has practicallyspent itself, and an inlet valve for 2,.

opening the valve inlet to the explosion chamber while the by-pass isclosed.

3. lin a gas engine, the combination of a pair of cylinders of differentsize forming lili respectively explosion and vacuum cham- L 'f bers, adi`erential piston, a valved by-pass leading from the explosion chamberto the vacuum chamber,- a valved exhaust port, a fuel inlet port, valvemechanism which opens the by-pass and closes the exhaust port andestablishes communication between the In testimony whereof I aix mysignature two cylinder chambers after the force of the in presence oftwo witnesses.

exhaust blast has practically spent itself, ROBERT MILLER.

and means for opening the fuel inlet to the Witnesses: 5 explosionchamber' while the by-pass is RHESA G. DU Bois,

closed. C. B. SGHROEDER.

